In Vivo Comparison of Knee Kinematics for Subjects Implanted With Either a ConforMIS or Traditional Knee Implant

NCT01882751 | Completed FDA Device

• 1 other identifier: Komistek 2
• Study Type: observational
• Target: 66
• Locations: 1 country
• Sites: 2

Brief Summary

A better understanding of knee joint kinematics is important to explain the premature polyethylene wear failures within total knee arthroplasties (TKAs) and to help design a prosthesis that most closely approximates the normal knee. Previously, most experimental studies of knee kinematics have involved cadaveric, in vitro analyses, or have not tested the knee in a weight-bearing mode. Others have used exoskeletal linkages and skin markers that permit error due to undesired motions between markers and the underlying bone. More recently, fluoroscopy has been used to assess in vivo kinematics for subjects having a TKA. ConforMIS has attempted to follow a clearly different path than the major orthopaedic companies. They have chosen to offer patients a personalized knee implant based off of each patient's femoral and tibial bone geometry. The hypothesis is that these subjects will experience a more normal-like kinematic pattern, eliminating paradoxical anterior sliding during weight-bearing knee flexion. Therefore, the objective for this study is to analyze the in vivo kinematics for 25 patients implanted with a personalized ConforMIS TKA and 25 patients implanted with a traditional TKA design to determine if there are any kinematic differences between these TKA designs.

Conditions

Complications; Arthroplasty

Keywords

kinematics; knee joint

Outcome Measures

Primary Outcomes (4)

• Kinematic Patterns during gait

  There are multiple parameters captured by fluoroscopy that will be assessed during these 4 activities including: 1. Anterior/posterior medial and lateral condyle contact positions 2. Axial rotation of the femoral component relative to the tibial component 3. Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface 4. Weight-bearing range-of-motion.

  at least 6 months post surgery

• Kinematic patterns during deep knee bend

  There are multiple parameters captured by fluoroscopy that will be assessed during these 4 activities including: 1. Anterior/posterior medial and lateral condyle contact positions 2. Axial rotation of the femoral component relative to the tibial component 3. Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface 4. Weight-bearing range-of-motion.

  at least 6 months post surgery

• Kinematics patterns during going up and down stairs

  There are multiple parameters captured by fluoroscopy that will be assessed during these 4 activities including: 1. Anterior/posterior medial and lateral condyle contact positions 2. Axial rotation of the femoral component relative to the tibial component 3. Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface 4. Weight-bearing range-of-motion.

  at least 6 months post surgery

• Kinematics patterns during getting up from chair

  There are multiple parameters captured by fluoroscopy that will be assessed during these 4 activities including: 1. Anterior/posterior medial and lateral condyle contact positions 2. Axial rotation of the femoral component relative to the tibial component 3. Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface 4. Weight-bearing range-of-motion.

  at least 6 months post surgery

Study Arms (2)

ConforMIS

Patients with ConforMIS implants

Device: Conformis CR Total Knee Replacement

Standard Total Knee Implant

Patients implanted with standard total knee implant

Device: Off the Shelf

Interventions

Conformis CR Total Knee Replacement DEVICE

iTotal CR by Conformis

ConforMIS

Off the Shelf DEVICE

A standard knee replacement not using ConforMIS' iFit technology

Standard Total Knee Implant

Eligibility Criteria

• Age: 40 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients who are at least 6 month post-op with a ConforMIS knee replacement or a standard total knee replacement who meets the inclusion/exclusion criteria

You may qualify if:

• At least 6 months post-op
• Between 40-70 years of age
• Body weight of less than 250lbs
• TKA patients will be judged clinically successful with an American Knee Society score of greater than 90
• Must have post-op passive flexion of 100 degrees with no ligamentous laxity or pain
• Participants must be able to walk on level ground without aids and ascend/descend stairs without assistance.
• Subjects will either a ConforMIS™ TKA or a traditional TKA manufactured by any other orthopaedic company.
• Patients must be between 160cm (5'3) and 193cm (6'4) tall.

You may not qualify if:

• Subjects not willing to sign the Informed Consent and HIPAA forms to participate in the study
• BMI \>40
• Pregnant females
• Surgical procedures conducted within the past 6 months other than TKA
• Subjects from the physician's list who do not meet study requirements
• Unwilling or unable to comply with study requirements
• Participation in another clinical study which would confound results

Sponsors & Collaborators

• Restor3D: lead

Study Sites (2)

Tennessee Orthopaedic Clinics

Knoxville, Tennessee, 37923, United States

Location

University of Tennessee

Knoxville, Tennessee, 37996, United States

Location

Study Officials

• Richard D Komistek, PhD

  Univeristy of Tennessee

  PRINCIPAL INVESTIGATOR

• Harold Cates, MD

  Tennessee Orthopaedic Clinics

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 21, 2013
• First Posted: June 20, 2013
• Study Start: June 1, 2013
• Primary Completion: July 1, 2017
• Study Completion: August 1, 2017
• Last Updated: October 25, 2023

Record last verified: 2023-10

Data Sharing

• IPD Sharing: Will not share

Locations

US (2)